Vibro-acoustic behaviour in biosourced composites

Abstract

100% natural composites comprising low protein content wheat flour and bamboo fibers were elaborated by means of an extrusion process using glycerol, water and sorbitol as plasticizers. The morphology, the mechanical properties and the acoustic response of the materials were analysed by means of scanning electron microscopy (SEM), tensile testing and acoustic measurements respectively. The extruded samples showed randomly dispersed bamboo fibers in the wheat flour matrix whereby a clear reinforcement in mechanical properties was observed with increase of the fiber percentage up to 15% w/w. The vibro-acoustic measurements performed by analysing the surface wave propagation of the sound signal show the effects of the fiber dispersion and of the frequency on the damping properties of these new composites. At low frequency, the presence of the fibers is well observed and they play the role of secondary wave sources. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.